Hello, proud new owner of a 87 ps190 indmar351 vd1:1. I recently rebuilt the carb, a 4160 list 50419-1, assuming it would fix the no idle condition. The boat idles great now, but runs rich as heck up and down. Could this be a power valve issue (put in a 2 in/hg), or something else? Any insight from a carb expert would be great. Thanks!

Agreed more info would be good. Your carb is old enough to have had the power valve ruptured from a backfire. Holley part #125-500 is an update for 1989 and older carbs. To test your power valve, while holding the large end, try to turn the small end. If it will turn, the valve is shot. If it won't turn, the valve still works. A blown power valve goes to full rich and the boat is barely drive-able, and will be leaving some black smoke.

Another possibility for running rich is a choke set too rich. Your choke should open fully within one minute of start-up.

Agreed more info would be good. Your carb is old enough to have had the power valve ruptured from a backfire. Holley part #125-500 is an update for 1989 and older carbs. To test your power valve, while holding the large end, try to turn the small end. If it will turn, the valve is shot. If it won't turn, the valve still works. A blown power valve goes to full rich and the boat is barely drive-able, and will be leaving some black smoke.

Another possibility for running rich is a choke set too rich. Your choke should open fully within one minute of start-up.

You are way to good, did you write the service manual my friend?

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Usually if there is a power valve problem it will not idle very well and it will run extremely rich. the power valve should be a 2.5. Since you just recently rebuilt the carb you may have squirreled out the power valve gasket which will dump gas pass the power valve. Check your oil and make sure you are not dumping fuel into your crankcase. You can pull off the front fuel bowl and check the gasket behind the power valve. You also need to check your float adjustment in the front fuel bowl. Which is probably the problem since like I mentioned earlier a power valve problem creates an idleing problem.

Today I checked both floats and needles. They appear parallel and are seating correctly. From what I can tell the power valve gasket is seated and sealing correctly. The choke is functioning correctly and has been adjusted. I also put in the old needles and the symptom persisted. The only thing I can think of is the power valve in the kit was defective or the wrong type, as the old one had a broken diaphragm. Do i need to worry about the accelerator pump or any other components? I will go through the carb again and verify all gaskets are sealed. Thanks for all the replies.

I cannot read any of the four numbers on the old power valve, damaged by corrosion. I also tested the carb for a blown power valve by adjusting the idle mix screws all the way in and the engine did not die. Im ready to give up and buy a new or reman carb. Does anyone have any recommendations? The cheapest I found was from I-5 carburetor for $300.00.